Feature Library part using Weldments

I'm using SW2018. I'm not super familiar with how the Feature Library works, but I've been working on a lot of structural projects using weldments... is it at all possible to create a Library part from a Weldment such as L3x3 angle that has holes/slots for tying in beams/channel and maintains it's cut list properties? Can I also have the cut feature put the holes in the adjacent beams? This would cut a lot of time out having to draw every single tie-in location. I tried making the piece and dropping it in to my model, but it doesn't recognize that it is a weldment profile and doesn't have a cut length. Is this even possible? Is there any other way to streamline making tabs and such like some of the Add-ins like SteelDetailer and Builtworks does? I get that I could make it an assembly and just drop parts where needed but that's what I'm trying to avoid

SolidworksWeldments